Watermelon-derived carbon nanodots make efficient optical sensor

doi:10.1038/nindia.2017.159 Published online 22 December 2017

Researchers have invented an
optical sensor that can detect minute traces of creatinine, a waste product that,
when abnormally high in blood and urine, signals ailing kidneys1.
This sensor is potentially useful for detecting kidney failure at an early
stage.

High levels of creatinine in
blood and urine are linked to various diseases including kidney failure.
Current methods for detecting creatinine are complex and expensive.

To develop a simple and efficient creatinine sensor, scientists from the Indian
Institute of Technology, Madras, and the Indian Institute of Science, Bangalore,
led by Mukesh Doble, fabricated an optical sensor by using a nanocomposite made
of gold nanoparticles and carbon nanodots prepared from the juice of watermelon
pulp.

The nanocomposite, coated with
an animal protein, detected creatinine more efficiently than existing sensors. The
nanocomposite easily entered specific mice cells and human cervical cancer
cells, and made these cells emit bright green and red light, indicating that
the glow came from the nanocomposite.

Results show that the
nanocomposite could even be used as a tool for multicolour labelling of
bacteria and animal cells. Besides its potential to detect creatinine, the
nanocomposite could be used to make light-emitting probes and tools for
cellular imaging.